Acetylshikonin attenuates angiotensin II-induced proliferation and motility of human brain smooth muscle cells by inhibiting Wnt/β-catenin signaling

Cerebrovascular smooth muscle cell proliferation and migration contribute to hyperplasia in case of cerebrovascular remodeling and stroke. In the present study, we investigated the effects of acetylshikonin, the main ingredient of a Chinese traditional medicine Zicao, on human brain vascular smooth muscle cell (HBVSMCs) proliferation and migration induced by angiotensin II (AngII), and the underlying mechanisms. We found that acetylshikonin treatment significantly inhibited AngII-induced HBVSMCs proliferation and cell cycle transition from G1 to S phase. Wound-healing assay and Transwell assay showed that AngII-induced cell migration and invasion were markedly attenuated by acetylshikonin. In addition, AngII challenge significantly induced Wnt/β-catenin signaling activation, as evidenced by increased β-catenin phosphorylation and nuclear translocation and GSK-3β phosphorylation. However, acetylshikonin treatment inhibited the activation of Wnt/β-catenin signaling. Consequently, western blotting analysis revealed that acetylshikonin effectively reduced the expression of downstream target genes in AngII-treated cells, including c-myc, survivin and cyclin D1, which contributed to the inhibitory effect of acetylshikonin on HBVSMCs proliferation. Further, stimulation with recombinant Wnt3a dramatically reversed acetylshikonin-mediated inhibition of proliferation and cell cycle transition in HBVSMCs. Our study demonstrates that acetylshikonin prevents AngII-induced cerebrovascular smooth muscle cells proliferation and migration through inhibition of Wnt/β-catenin pathway, indicating that acetylshikonin may present a potential option for the treatment of cerebrovascular remodeling.     

人工基因元件的生理学研究进展

按照工程学原理人工设计的基因元件应该是模块化的,同时具备可预测地组装和再利用的属性。然而,真正的细胞生理条件下各种层次的生理干涉效应会严重地阻碍人工基因元件的功能性组装,即大多数组装后的人工系统完全或部分丧失预设功能。我们提出合成生理学的概念,将其定义为研究和控制人工生命系统与底盘细胞生理系统相互作用的合成生物学分支领域。在此框架下,本文归纳了细胞生理系统与人工基因元件的相互干涉方式,并对表征和消除这种相互作用的技术方法和设计策略进行综述。     

A Case Study of the Dynamics of In Vitro DNA Evolution Under Constant Selection Pressure

Although thousands of in vitro selection and evolution experiments have been performed to seek different types of targets, most of them have only inspected the terminal evolutionary pool for patterns. In addition, to rapidly obtain the most favorable target, many experiments have been carried out under increasing selection pressure. However, increasing selection pressure seldom occurs in natural evolution. We studied the dynamic features of DNA in vitro evolution in the presence of the Mnt repressor under sequential constant selection pressure. When evolving under a constant pressure from an initial random pool of DNA, our system showed a clear, sharp, and reproducible crossover from a random population to an advantageous population (higher binding affinities of DNA sequences to the Mnt repressor). This crossover occurs after a long latent period during which there are no obvious changes in the population phenotype. We demonstrated that the existence of the crossover is caused by a significant sequence-nonspecific binding in the repressor–DNA system. After the crossover, the population settled in a stationary distribution of genotypes, which responded immediately to a subsequent sudden increase in selection pressure. We also experimentally tested the linear correlation between the evolution speed and sequence diversity (Fisher’s theorem) in our system. X. Yang and X. Liu contributed equally to this work.     

Microbial diversity in acid mine drainage of Xiang Mountain sulfide mine, Anhui Province, China

To understand the composition and structure of microbial communities in acid (pH 3.0) mine drainage (AMD) associated with pyrite mine tailings in Anhui Province, China, molecular diversities of 16S rRNA and 18S rRNA genes were examined using a PCR-based cloning approach. Bacterial, archaeal and microeukaryotic clone libraries were constructed. In contrast to typical dominance of autotrophic acidophiles, genus Acidiphilium, which consists of mixotrophic acidophiles capable of chemoorganotrophic and photosynthetic metabolisms, was the largest group in the bacterial clone library. These mixotrophic organisms may be advantageous in the oligotrophic AMD environment of the study site (certain amounts of dissolved organic carbon and light) by switching between two modes of metabolisms. Unexpectedly, a large fraction of bacterial clones (12.7%) were related to the neutrophilic genus Legionella, which can cause Legionnaires’ disease, a potentially lethal pneumonia. The eukaryotic 18S rRNA gene sequences were mostly related to Oxytricha, Nuclearia, and Penicillium. In the archaeal clone library, all the sequences were affiliated to the phylum Crenarchaeota, while the Euryarchaeota was not present.     

Oral Hepatoprotective Ability Evaluation of Purple Sweet Potato Anthocyanins on Acute and Chronic Chemical Liver Injuries

In recent years, chemical liver injury cases increased significantly in Asian countries, and the imbalance in redox system was believed to be the main cause. Purple sweet potato anthocyanins (PSPA) have been shown to exert antioxidant activity and oxidative-stress-associated functional protein modulation through various signaling pathways, so it is considered to have the potential of liver injury preventive activity. In order to evaluate the hepatoprotective potency of PSPA according to its free radical scavenging and antioxidant effects, three acute chemical liver injury models were set up with ethanol, acetaminophen and carbon tetrachloride. PSPA at moderate and high doses obviously attenuated the tested serum biomarker levels and liver index in our experiments. Besides, one chronic liver injury model set up with carbon tetrachloride was also applied, in which PSPA was orally administrated after the liver damage had been formed. Both the serum biomarker levels and histopathological analysis showed that PSPA was able to attenuated chronic liver injury. Our experimental results demonstrated the potential of PSPA as an oral hepatoprotective agent against chemical liver injury from food plant.     

广东连州田心省级自然保护区珍稀濒危植物资源现状及优先保护初步研究

掌握保护区珍稀植物本底与受威胁状态,完善保护区珍稀植物的优先保护评价体系,可为保护区制定保护对策、科学管理提供依据。通过资料收集和实地考察,对连州田心省级自然保护区珍稀植物资源开展研究,结果表明,田心省级自然保护区共有珍稀植物35科63属94种,其中国家重点保护野生植物有25科33属46种,广东省重点保护野生植物有7科10属10种,中国植物红皮书稀有濒危植物20科25属25种,CITES公约附录植物5科23属46种。采用优先保护评价体系对41种代表性珍稀濒危植物进行排序,结果属Ⅰ级保护的有2种,占评价总数的4.88%;属Ⅱ级保护的有22种,占评价总数的53.66%;属Ⅲ级保护的有17种,占评价总数的41.46%。田心省级自然保护区生境良好,珍稀濒危植物种类多,数量丰富,具有较高的生态保护价值。该评价体系对41种植物的评价与分级结果更真实地反映了它们在田心保护区受威胁状态和优先保护顺序,对该区珍稀濒危植物的优先保护工作具有一定指导意义。     

利用假型反转录病毒对大部分胰腺切除后再生细胞的世系追踪

胰腺是一个重要的内外分泌混合腺, 胰腺发生损伤后能够再生。为了探讨胰腺活体细胞世系追踪的方法和胰腺损伤后再生细胞的来源,分别通过胰腺伤口涂抹并胰内注射、尾静脉注射及腹腔注射三种方法, 利用假型反转录病毒对成体小鼠大部分切除后胰腺的细胞进行世系追踪。结果发现在活体条件下, 与尾静脉注射及腹腔注射法相比, 胰腺伤口涂抹并胰腺内注射反转录病毒的方法能够更有效的标记胰腺细胞; 而且, 通过对标记细胞的世系追踪研究证明, 在胰腺损伤后, 胰腺腺泡细胞能够接受损伤信号刺激发生再生。为今后进一步利用反转录假病毒对活体胰腺进行细胞命运追踪研究奠定基础, 为利用反转录病毒载体进行胰腺疾病的基因治疗提供线索。